I also suffer from these dreadful feelings. I have always had the tendency to fixate on things, especially concerning my health (and more recently, the health of my loved ones). Just like you, my family has always made a joke out of it and although my boyfriend understands, I have felt sillier and sillier coming to him with the constant issues. I fear that one day something will actually be wrong with my health and no one will believe me. I wish I had the answer to stopping your obsessive thoughts. I know that for me, it must be stress related. My boyfriend is the one that pointed this out to me: he calls my obsessions my "flavor of the week." It made me angry at first, but I realized how completely true it is. He brings to my attention the stressful things I have going on in my life and says, "and instead you're worrying about what your headache means...last week it was your jaw pain." It's completely true. Try and alleviate the stressors in your life. Exercise, meditate, anything to concentrate your energies somewhere else. I've always carried my stress physically or in these weird mental manifestations, so it's hard to tell when it's stress causing your problems. Take a second to really evaluate what is going on in your life and more often than not I guarantee that your obsession is just a coping mechanism. The more you find that pattern in your life, the more convinced you'll be that there's nothing actually wrong with your health and that it's more likely just your mind. Stay strong